The Cottage is in Montgomery town itself, just off the market square. It's detached and used to be a pub, which you can still tell from the layout. The front room has high ceilings. It's on a bit of a slope so the views from the front are good, over towards the castle.
It sleeps eight, in four bedrooms. There are three bathrooms, which helps with that many people. It's got a 5 Star rating, so it's well-equipped and finished to a good standard. The garden is enclosed and there's a private hot tub you can use.
Montgomery Castle is right there, a five minute walk up the hill. It's a ruin, but it's free to wander around and the views are worth it. The Offa's Dyke Path runs close by if you want a proper walk.
You're well placed for a few National Trust places. Powis Castle is about 20 minutes away near Welshpool, the gardens are famous. Chirk Castle and Erddig are a bit further, maybe 40 minutes towards the border. Shrewsbury is half an hour's drive for a bigger town day out.
Facilities wise: it's got everything on the list. Washing machine, dishwasher, woodburner, WiFi, TV. Bedding and towels are included. There's a cot, highchair and stairgate if you need them. You can bring up to two pets. Parking is on site.
Useful links: Offa's Dyke Path and Visit Wales Mid Wales.